1. Field of the Invention
The invention is directed to a laser radiation source having a vertical stack of laser diode elements.
2. Description of Related Art
In industrial laser material processing as well as in medical engineering, high-power diode lasers in the form of laser diode bars which can be stacked to form two-dimensionally emitting surfaces with an elevated radiation output are generally used for pumping solid state lasers.
Out of the numerous suggestions for stacks, as they are called, U.S. Pat. No. 5,923,692 A describes a high-power diode laser array formed of vertically stacked laser diode bars which are contacted via electrically conducting substrate layers. By means of one of the substrate layers, thermal contact is made with a thermally conductive, electrically insulating carrier plate that is connected to a heatsink. The laser diode bars are connected in series in that the electrically conducting substrate layers of adjacent laser diode bars are directly bonded to one another.
This is disadvantageous on the one hand in that thermo-mechanical stresses can occur because the laser diode bars are interconnected as well as being connected to the carrier plate. On the other hand, variations in thickness in the laser diode bars and electrically conducting substrate layers lead to variations in the spacing between the laser diode bars.